Electric-circuit breaker



G. F. HUNTER. ELECTRIC cmcun BREAKER.

APPLICATION FILED MAR. 27, I920. RENEWED OCT. H. I922.

Patented Dec. 12, 1922.

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Patented Dec. 12, 1922.,

UNITED STATES PATENT OFFICE.

GEORGE F. HUNTER, OF PORTLAND, OREGON.

ELECTRIC-CIRCUIT BREAKER.

Application filed March 27, 1920, Serial No. 369,163. Renewed October 11, 1922. Serial No. 593,894.

' To all whom it may cmwern:

Be it known. that I, GEORGE F. HUNTER, a citizen of the United States, residing at Portland, in the county of Multnomah and State of Oregon, have invented a new and useful Improvement in Electric Circuit Breakers, of which the following is a specification, reference being had to the accompanying drawings.

My invention relates to circuit breakers as a class.

The object of my invention'is to proi'ide a circuit breaker wherein the parts are arranged in a manner that when the breaker is heated to a pre-determined degree it will open the circuit and when its temperature is reduced to said degree, or below, it will close the circuit. These objects, as well as others, I accomplish by the construction, combination and arrangement of parts illustrated in the accompanying drawings which form a part hereof.

The single figure illustrates a curling iron, with parts in section, and aside view of the circuit breaker associated therewith.

The instrument is a curling iron 01" a com,- mon type. It has a handle 1 and heating iron 2, having a clasp 2'. Inthe end of the handle a socket of common form is provided. The metallic part 3 of the socket forms one terminal and the opposing insulated terminal 4 is within the socket as shown. These receive the plug at the ends of wires extending from a source of electric energy. A conducting wire 4 extends from the terminal 4 to a connection with a resistance coil 5 in the heating iron 2. The return conducting wire '6 of the coil 5 extends to an insulated, rigidly secured contact terminal 7 in the central part of the handle 1. A conducting wire'3 extends from the terminal 3 to an insulated securing means 8 to which it is fastened. An angled, thin metal arm 9 is rigidly fas tened at its shorter end within the securing means 8. The longer free end extends forwardly in the handle to a position opposite the terminal 7. In the free end of the arm a threaded contact pin 10 is rotatably positioned. A coil spring 11 is placed about it to prevent it from rotating from a set position. The pin has a slotted head or any convenient arrangement to facilitate rotating it. An opening 12 is provided 1n the handle to supply means of access to the pin.

- The arm 9 is of a desired thickness and length, and the contact terminal -..7 is artemper.

ranged in a position oppositely disposed to the inner end of the pin, which is adjustable toward said tern'lina It will be seen that when the iron 2 attains a desired heat, the pro-determined form and arrangement of the arm 9, is such that the said heat, being conducted through the iron 2 to its base in the handle will cause the arm 9 to acquire a temperature which will cause it to expand and the pin to recede from the terminal 7, thus opening the circuit. It will also be seen that when the temperature in the arm 9 is reduced to a desired degree, it will contract and cause the pin 10 to again engage the terminal 7 and close the circuit. It will be understood that the pin is first adjusted to a position wherein I it will retain the circuit closed until the said desired temperature is attained when itautomatically opens the circuit as stated. It is intended that the arm 9 shall have a short part and a longer part of desired lengths, the metal being of a predetermined When an arm of this form is thus bent, the metal on the inside of the angle is compressed and that on the outer side expanded. Upon the arm being heated, the

thermal action causes the metal on the inside of the angle to expand more than that on the outside of the same, which has been stretched in shaping the arm. This thermal action causes the longer part to Warp away and draws the pin 10 from the terminal 7, thus breaking the circuit. As the temperature of the arm decreases, the action of the integral metal parts about the angle is reversed and the arm moves the pin again into contact with the terminal 7. I contend that the single arm circuit breaker, of a form and length related to the laws of thermal action, furnishes a very sensitive and eflicient means for breaking the electric circuit whenever the temperature in adjacent parts of any in strument to which it is adapted, has risen to a predetermined degree. The device can be adapted to electric ovens,flat irons or any utensil in which heat is produced by electrio energy.

I claim In an electrical circuit having opposing terminals and a resistance coil in the circuit arranged to diffuse heat therefrom, an angled metal. arm of pie-determined temper, formed with long and short parts of desired lengths and thickness. the short part being rigidly connected with one of the circuit terminals, the free e ll 0t thq longer part the ()ppuslng' terminal aml. when the heat disposed to the other (.ll'tflllt tcrmmul, the

arm being formvd untl arrung'ml 1) that upon t l-ecen'ulg heat thereln the metal about the Illa insule of 1ts angle Will he thermally expanded and allow the longer part of thov arm to Warp and draw 1135 Contact polnt tree 01? point to engage suhl terminal.

Witnesses H. E. BRADLEY, C. \V. THOMPSON. 

